1. Field of the Invention
The invention relates to providing digital content to network elements, such as end user set-top boxes and other processing devices, in a switched digital video (SDV) system. More particularly, the invention relates to providing encoded digital content to network elements based on the decoding capabilities of the network elements.
2. Description of the Related Art
Many conventional network elements, such as end user set-top boxes and other digital content processing devices, are configured to decode video (and data) content that has been encoded using an MPEG-2 (Moving Pictures Expert Group) compression algorithm codec (coder-decoder). The cable industry has standardized the delivery of MPEG-2 video content at 3.75 Mbps (Megabits per second) for standard definition televisions. The bandwidth of MPEG-2 video content balloons to between 12 Mbps and 19.2 Mbps for high definition (HD) video content.
Video content encoded according to the MPEG-4, Part 10 video compression standard uses approximately 50-70% of the bandwidth of MPEG-2 video content, yet with the same or better quality as MPEG2 video content. MPEG-4, Part 10 video compression, which also is referred to using the terms H.264 and AVC (advanced video coding), is referred to herein simply as MPEG-4.
The cable industry has begun a shift towards encoding video content using an MPEG-4 (or similar) codec. For example, at least one television network has announced that they will deliver the high definition television (HDTV) versions of all their channels to cable headends using MPEG-4 encoding. However, an MPEG-2 decoder typically can not decode video content that has been encoded using an MPEG-4 encoder.
Digital set-top boxes and other network elements soon will be introduced that will be able to decode both MPEG-2 and MPEG-4 video. Once this introduction occurs, the content distribution systems will contain existing (legacy) set-top boxes and network elements that can decode only MPEG-2 signals, as well as newer, more advanced set-top boxes and network elements that can decode both MPEG-2 and MPEG-4 signals. Also, it likely will take many years, and perhaps a decade or more, to transition all set-top boxes and network elements to support MPEG-4 video. During this transition, it likely will not be possible to broadcast all video content channels in both MPEG-2 and MPEG-4 format, due to bandwidth constraints.
Accordingly, there is a need for a system and corresponding devices that can be used to manage the transition from MPEG-2 to MPEG-4, and to reduce the bandwidth needed by the system until such transition is complete.